FRP-to-metal bonds: effect of test specimen configuration on interfacial Stresses

Metallic construction materials can be strengthened relatively easily and effectively with externally bonded fibre-reinforced polymer (FRP) composites and in order to understand the bonded interface, researchers have tested FRP-to-metal bonded joints. Despite several different joint configurations being employed to date, no systematic investigation has yet been conducted on the effect of different configurations. This paper presents the results of a finite element investigation on the interfacial stresses induced in different FRP-to-metal joint test configurations. The distributions of interfacial shear and normal stresses are determined for single-shear and double-shear joints in which either the metal or FRP is loaded and the relative differences and similarities are also established between the joints under investigation. A fictitious FRP-strengthened beam is then modelled and specific joint configurations which most accurately represent the interfacial stress distributions in the beam at selected locations are identified. The findings of this study will aid researchers in selecting FRP-to-metal joint configurations most appropriate for representing the interfacial stress states in different FRP-strengthened member scenarios.